High temperatures during the summer months are a common feature in countries with a Mediterranean climate, such as Cyprus and Greece. However, anthropogenic climate change is responsible for the increase in the frequency, intensity and duration of extreme high temperatures in the wider Eastern Mediterranean region, especially since 1990. At the same time, future climate projections show that high temperatures and heatwaves that were observed at the beginning of the 21st century and characterized as extreme will become the norm in the coming years. This study confirms the increasing trend in maximum and minimum temperature for the last four decades in Cyprus. Bioclimatic indices provide a measure of human thermal discomfort caused by the thermal environment. In the present study, the UTCI index from the dataset ERA5-HEAT was used to estimate the heat stress of the average person under conditions of heat events. The spatial distribution of maximum monthly UTCIdaily values was carried out for the period 2004–2019. At the same time, the correlation of patient admissions to hospitals, as well as the relationship of mortality with high UTCIdaily values, was assessed. Mortality data and data from eight public hospitals located in five districts of Cyprus were analyzed as obtained from the Ministry of Health and the Cyprus Statistical Service. The data reveal that UTCIdaily values were positively associated with hospital admissions and mortality in some cases.